CRITICAL CURRENTS AFTER THERMAL-NEUTRON IRRADIATION OF URANIUM DOPED SUPERCONDUCTORS

Fission fragment damage was introduced into aligned sintered samples of various superconductors containing small additions of UO2 by irradiation with thermal neutrons. Samples of aligned, sintered YBa2Cu3O(x), powdered Bi2Sr2Ca1Cu2O(y), powdered Bi1.7Pb0.3Sr2Ca2Cu3O(z), and epitaxial films of YBa2Cu3O(x) on (100)SrTiO3 were used. Magnetic hysteresis, with the critical state model, was used to evaluate changes in the intragranular critical current. In the case of the Bi1.7Pb0.3Sr2Ca2Cu3O(z) powders an increase in intragranular J(c) at 0.8 T of greater than 70 times was produced by the radiation. The epitaxial film showed no change in J(c) on irradiation. This behavior upon irradiation is attributed to the pinning caused by damage produced by the fission products of uranium.